A mountain stream, or a river flowing lower down in the valley.
The Nile is a north-flowing freshwater river.
It could be a river.
Perhaps, flowing, stagnant, and potable ( fit for human drinking ).
Freshwater and ocean ecosystems interact through the water cycle, with freshwater from rivers and streams ultimately flowing into the oceans. This connection allows for the transfer of nutrients, species, and energy between the two ecosystems. For example, some marine species such as salmon may migrate from the ocean to freshwater rivers to spawn, while coastal wetlands can act as important nurseries for both freshwater and marine species.
Loaches are freshwater fish, for example, the clown loach which is a freshwater fish.
That's a river.
It might be considered a creek or stream.
There are two general terms that categorize freshwater ecosystems. Lentic refers to standing bodies of water (lakes, ponds, and inland wetlands) while lotic refers to flowing systems (streams and rivers).
Freshwater ecosystems include flowing rivers, lakes, ponds, and wetlands with low to no salt content. These habitats support a variety of organisms such as fish, amphibians, plants, and invertebrates adapted to thrive in freshwater environments. Freshwater ecosystems play a crucial role in regulating water quality, supporting biodiversity, and providing valuable ecosystem services.
A natural underground spring.
Excessive freshwater (rain) flowing into a shallow sea can change the salinity.
Excessive freshwater (rain) flowing into a shallow sea can change the salinity.